Invadopodia (image) University of Pennsylvania School of Medicine Caption This is a segment of the mutant intestine (3.5 day old fish, lateral view of the intestine) in a transgenic mutant zebrafish that expressed the green fluorescent protein tagged to a peptide that binds to actin in epithelial cells. Invasive cells with protrusions expand out in to the surrounding tissue stroma (arrows). The green structure on the top of the movie frame is the kidney duct. The intestine is below the kidney duct. The actin-rich protrusions are the invadopodia. Credit Christoph Seiler and Michael Pack, Perelman School of Medicine, University of Pennsylvania Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.